1. Field of the Invention
This invention relates to new fluorine-containing polyamide-polyamide polymers and polybenzoxazole-polyamide polymers derived therefrom which exhibit improved thermal stability, improved resistance to solvents, good processability, good film-forming properties and good film characteristics.
2. Description of Related Art
Polyamides derived from aromatic diamine and aromatic di-acid monomers are widely used in the aerospace industry and electronics industry because of their toughness, low density, thermal stability, radiation resistance, mechanical strength and good dielectric properties. However, such polyamides are often difficult to process thermally and thin films prepared therefrom are often brittle and lack acceptable optical transparency.
U.S. Pat. No. 3,179,635 discloses the preparation of polyamide-polyimide polymers said to have good thermal stability and good film-forming properties which may be prepared by condensing a tetra functional aromatic dianhydride, and aromatic diamine and an aromatic acid halide. Polyamides and polybenzoxazole derivatives thereof based on the condensation product of aromatic diamines and aromatic dicarboxylic acids and their derivatives are disclosed in U.S. Pat. Nos. 3306876, 3449296 and 4622285. U.K. Patent Application GB-2188936A discloses the preparation of polyamides and polybenzoxazole derivatives thereof based on the condensation product of 2,2-bis(3-amino-4-hydroxyphenyl)-hexafluoropropane with an aromatic dicarboxylic acid or acid halide, followed by cyclization of the polyamide to form a polybenzoxazole. Similar fluorine-containing polyamides are disclosed in U.S. Pat. No. 3328352.
In Applicant's co-pending application Serial Number 915,342, filed in the United States Patent and Trademark Office on October 2, 1986, is disclosed hydroxy or alkoxy substituted polyamide polymers which, in the preferred embodiment, are prepared by forming the polymeric condensation product of hexafluoro-2,2-bis(3-amino-4-hydroxyphenyl) propane and an aromatic di-acid halide. These polymers are particularly useful in the preparation of photoresist compositions and may also be converted to the corresponding polybenzoxazoles by cyclization. Similar polyamides and polybenzoxazole derivatives thereof based, in the preferred embodiment, on the polymer condensation product of 4,4'-bis[2-(3-amino-4-hydroxyphenyl) hexafluoroisopropyl]diphenyl ether and one or more aromatic di-acid halides are disclosed in U.S. Pat. No. 4,845,183, the disclosure of which is incorporated herein by reference.
Whereas the above-referred to polyamide and polybenzoxazole polymers are useful for the utilities disclosed, it is desirable to provide polyamide-polyamide polymers and polybenzoxazole polymers derived therefrom which provide not only superior thermal and thermooxidative stability, but also excellent thermal processability, low moisture uptake, low dielectric constant and good film-forming properties and film characteristics.